This invention relates to the stabilization of radial block copolymers of a monovinyl-substituted aromatic compound and a conjugated diene.
Radial block copolymers of a monovinyl-substituted aromatic compound and a conjugated diene such as styrene and butadiene are known in the art, and are useful for a variety of purposes. However, for some applications it is desirable that the polymer be rendered more stable against thermally induced degradation. It is known to add a variety of different types of stabilizers to various types of polymers to protect same against deterioration. Nevertheless, in some instances radial block copolymers stabilized with conventional systems exhibit a particular type of deterioration which is evidenced by drop off in melt flow on heating for extended times, such as may be encountered in conventional fabrication operations involving extrusion and the like.